1. Technical Field
The present disclosure generally relates to electronic communication devices and in particular to electronic communication devices having dual antennas that can both transmit communication signals.
2. Description of the Related Art
Two-way communication devices, such as mobile telephones, two-way radios, and personal digital assistants, each use antennas to transmit and receive radio frequency (RF) communication signals. These antennas communicate with wide area network towers, local area network base stations, and even other devices directly, to transmit and receive data. The antennas allow the device to be truly wireless, in that all communication may occur through the air. Communication systems often optimize for total radiated power (TRP) and total isotropic sensitivity (TIS) in as many use cases as possible, such as free-space, handheld, and held to the ear. The TRP and TIS figures of merit combine conducted power levels or conducted sensitivity levels, respectively, with the antenna system efficiencies. The values provide a first-order estimation of how effective the communication device will be at maintaining a good quality of service. Generally-known methods for optimizing TRP include increasing the conducted power delivered to the antenna system or methods to improve the efficiency of the antenna system itself. Generally-known methods for optimizing TIS include improving the conducted sensitivity threshold or methods to improve the efficiency of the antenna system itself.
In optimizing TRP, the specific absorption rate (SAR) exposure of the user remains a topic of concern, and simply enhancing the TRP detrimentally impacts the SAR level also. Attempts to automatically mitigate SAR exposure of a user of a communication device who is using it in this manner have generally utilized the power control of the power amplifier of the RF front end, reducing the TRP level. While mitigating SAR exposure to an extent, such power reductions can reduce the quality of service (QoS) of the communication session. Similarly, the use case conditions in which SAR mitigation are required, i.e., held to the ear, impact the TIS of the device by naturally diminishing the efficiency of the antenna system.